Bezel dop and grinding device



Sept.- 14,1948. sPlRA I 2,449,423

' BEZEL nor AND GRINDING DEVICE Filed Sept. 1, 1945 2 965 75 .1. rqz.

INVENTOR Josgj' [filial S 51% llaATToRN EY l atentec'i Sept. 14, 1948UNITED STATES ri e FFICE 13 Claims. (Cl. 51-229) This invention relatesto the field of grinding or cutting facets upon gems, and moreparticularly to a dop for the formation of the crown or bezel facets,and to a method of forming the crown'or bezel facets.

This application is a continuation-in-part of my application Serial No.437,056, filed March 31, 1942, entitled Method for polishing or formingfacets on gems, diamonds or the like, and apparatus therefor, now PatentNo. 2,393,939, issued January 29, 1946.

In my prior application aforementioned, I have described and claimed anovel workholder or dop for the formation of the crown or bezel facetswhereby mechanically held stock may be axially mounted, and by indexingthe gem stock in the holder, the bezel or crown facets may be formedthereon by reason of the novel process I have devised.

Briefly, in my prior application, the process involves forming a brutedstock with a generally cylindrical portion axially disposed to the tableforming portion of the gem, then forming the pavilion or base facetsabout an axial line perpendicular to the table of said stock, therebyproviding an axial line of reference determined by the pavilion or basefacets and the table, whereby the bezel or crown facets may then beaccurately and symmetrically formed thereon.

While I have found that with the larger gems, say twenty or less to thekarat, my holder or dop for the formation of the crown or bezel facetsserves adequately for its intended purpose, I have found it economicallyunsuitable in my endeavor to extend the procedure to gems of the smallersizes, such as, for example, twenty or more to the karat.

I have also found inthe use of the crownor bezel dop of myaforementioned application that whether the small or large gems areemployed, there are also other economic losses involved in the wear andtear in replacing the table engaging member, due to the close clearancesentailed in the contact of the face of the table and its engagingmember. i Q

Accordingly, my present invention is directed to animprovement of myprior invention, and has for its object the provision of a holder or dopfor the formation of the crown or bezel facets, whereby the grinding ofsmall gems is made possible more economically than heretofore attainable, with accuracy inthe formation of the crown or bezel facets, andwith substantially the same accuracy in the shape and number of thefacets, to secure the highest degree of brilliancy in the gem,in amanner heretofore deemed uneconomical in respect of the so-called smallgems, and with unusual accuracy in the formation of the larger gems, sothat the employment of unusually skilled labor is avoided. 1

It is a further object of my invention to provide a crown or. bezelfacet forming assembly whereby the crown and bezel'may be quickly andeconomically formed, with accuracy, requiring minimum inspection andwith little disturbance caused by the wear of the parts ofthecontrivance due to the abrasion on the metal parts inworking' withdiamonds.

It is a further object of my invention to provide a workholder or dopfor the formation of the crown .or bezel facets in which, this highlyinaccessible portion of the gem may be worked accurately and facilely,without specially skilled labor, notwithstanding inaccuracies due to thenormal wear and tear of metallic parts in handling material ofthehardness or diamonds.

It is still further an object of my invention to provide an. improvedmethod for grinding and polishing the bezel or crown facets accuratelyto secure the maximum optical properties of the gem, while avoiding thelaborious use of cements in the dop by employing a mechanical means forholding the gem in position, in an indexing device.

Other objects of my invention reside in the provision of a workholderfor small objects, whereby surfaces in the nature of facets, may beground thereon symmetrically about the object, such as in forming thecrown or bezel facets, without any disturbing factor due toeccentricitywhich might occur, especially in mounting in the workholder theso-called small gems of twenty or more to the karat, where'purchase orholding surfaces are exposed to the minimum, and axial positioningexperiences considerable difficulty;

Still further objects of my invention reside'in the provision ofelectrically controlled means for automatically signalling; thecompletion, of 1 a facet-forming operation, whereby polishing operationsmay be economically practiced.

For? the attainment of these objects and such further objects as mayappear hereinor be hereinafter pointed out,.I make reference to theaccompanying drawing forming a part of this appli cation in which: I A

Figure 1 is a longitudinal sectional view ofa workholder or dop for theformation of the crown or bezel facets, and a fraginentary portion ofits mounting assembly; i i 1 Figure 2 is a side elevation taken in thedirection of lines- 2-2 of Figure 1; p a i Figure 3is'an end elevationtaken in thedirection of lines 3-3 of Figure 1; g

Figure 3A is a longitudinal sectional viewof Figure 1', magnifiedto showthe nose portion and connection to the wiring system;

Figure 4 is an enlarged perspective viewof a detail showing thecontacting element in' posi-. tion; i

Figure 5 is an enlarged perspective pavilion' engaging cone.

view of the I9I to form the frustum of a pyramid, with the main orlarger base adjacent the girdle and the upper base or smaller basecoincident with the surface of the table forming face I 92.

By retaining the angular position or slope to leave remaining duringgrinding a portion adjacent the girdle I9I cylindrical and unmodified,it will be apparent that the distance d between the perimeter of thegirdle G and the chord lying in the surface table, and whichforms theside of a regular polygon, is a constant.

Thus, by maintaining the rectangular gauge face I95 tangentially to thegirdle I9I at its perimeter, and axially extending a pin I90 at rightangles thereto, its end I91 may be utilized to measure or to gauge thedistance d.

For convenience of reference, I will refer to the distance d set off bytheend I91 and the gauge face 2I2 as the differential bi-apothem, whichmay be defined as the distance measured in the upper base of a frustumof a regular pyramid extending normally and diametrically from one sideof the regular polygon there defined to the point of intersection of aplane parallel to the axis and tangential to a circle circumsc-ri'bingthe regular polygon in the lower base.

It will also be observed that symmetry of the crown or bezel fawts isassured as long as the differential bi-apothem remains constant in theformation of facets upon the crown bezel, with a regular polygonadjacent the table of the gem, regardless of the possible eccentricityof the diamond stock in relation to the axis of the dop.

With this premise, I will now refer to the views wherein I provide agauge holder 200 comprising a generally rectangular plate, one end ofwhich is provided with fingers 20 I--29 I, inwardly turned to seat inorifices 203-203 formed in the sleeve I50. A spring clip 204 is anchoredby a screw 205 at one end. The free end 206 resiliently presses downupon the holder 200, thereby permitting pivotal movement of the gaugeholder I200. The free end of the gauge holder 200 is provided with abolt 201, having a riveted head 208, which clamps the L-shaped leaf 209to the holder 200. The L-shaped leaf 209 has a branch 2I0 which projectsthrough an orifice 2| I formed in the extension I66. The branch 2| 0terminates into a rectangularly shaped bearing end or gauge face I95,which is arranged to be urged by the spring clip 204 to contact theperimeter of the girdle of the stock D.

For convenience, the gauge face 2I2 will be referred to as the girdlecontact and the pin end I91 will be referred to as the control contactI91.

The bolt 201 previously described is fixed to th plate 200 by the nut2I3, and along the shank 2", the bolt is formed with a longitudinal slot2I5.

With the construction just described, there is then provided an L-shapedfine spring steel wire 2I6, of which the shorter branch 2I1 is disposedin the slot 2I5 by first mounting a coil spring 2I8 on the shank 2I4 ofthe bolt, thereupon positioning a washer 2I9 and gripping the branch 2 I1 in position by the nut 220.

The longer branch 22I extends against the face of the plate I14, whichis formed with a groove 222 deeper than the wire to center the free endand provide the control contact I91 previously mentioned. The branch 22Iis held in the groove 222 by the branch M0, to slide freely within thegroove, notwithstanding any pressure which the face I14 may exert uponthe table I92 of the stock diamond D, 1 a j It will thus be seen that avariable dimension may be secured between the free end 2I2 of the leafs209 and the contro1 contact I91 which may be extended to bear. upon thetable I93 of the stock D when guided in the groove 222. The contact I91projects beyond the apex I12 of the plate I08 and therefore leads in itscontact to the turn table or skeif 223.

The turn table or skeif .223 is usually made of cast iron upon whoseface diamond dust is provided for the polishing or facetting operation.as will be understood by the worker in the art. The shaft 224 thereofcarries a commutator 225, making contact with the conductor 226 leadingto a make and break device 221, which actuates a signalling or likedevice 228, then leading through the conductor 220 connected to the setscrew 205 on the sleeve I50. It will be apparent that the circuit willbe completed or made when the control contact I91 comes in contact, orreaches a predetermined closed circuit making position with the skelf223.

Having now described the installation, the operation of the mechanism isas follows: The bruted stock D with the pavilion facets I already formedthereon, is positioned upon the adapter'IGD to have the pavilion facetsin contact with the facets of the flared seat I 93, formed in theadapter I60, exposing the table I93 and the cylindrical section G. Theplate I68 with the branch 22I fitted within the groove 222 is thenavailed of to seat the stock D in position, care being taken to nest thefacets I90 and those on the flared seat I53 into contacting engage ment,and to press the surface I14 against the table forming portion I92. 1

The branch 22I should be free to move in the groove 222.

Pressure is then applied by the collar I16 to grip the gem firmly in thedop. When in this position, the branch 2 I 0 is then brought intocontact with the bruted girdle or cylindrical perimeter I9I. Thethickness of the branch 200 is calculated to exceed the height oraltitude of the cylindrical perimeter I9I and the layers forming thebranch 2I0 may be laminated or built up, or diminished, in accordancewith the height of this cylindrical perimeter.

With the stock D so positioned, by manipulation of the nut 220, thecontrol contact I91 is brought into the position which it is desired tohave, outlined on the table forming face I92 by the regular polygonaloutline P. The dop is thereupon mounted on the block 56 and theangularity'of the dop is adjusted in respect of the turn table or skeif223, to form the facet I94. This angular positionis one which willassure a. remnant of the circular perimeter I 9| and which, of itself,will be completely circular and which will be in constant contact withthe gauge face contact I95, previously mentioned, and referred to as thegirdle contact.

Upon effecting the grinding operations, the assembly gravitates or movesunder pressure with the diamond in contact with the surface of the turntable or skeif 223. This operation progres-- sively 'bringsthe controlcontact I91 into closer position .in respect of theskeiflto complete thesignal circuit when the proper depth of out has been reached. j 1 j I jI The assembly is then convenientlyraised, and then the hand wheel I83may be indexed preparatory to cutting the-next facet; The same operationis then repeated in accordance with the number of facets outlined .by.the regular polygonantenna 7 P, without any iother adjustment f'.:thec:conti:'ol contact.

;It'will be observed'thatiin view-of the fragment of circularcontour:left at .the periphery I 9 |,-the assembly automaticallyservestoiprovide a symmetrical formation .of the facets despite anyeccentricity of the -stock D :on 'the dop aor ;holder, since themeasurement, so to speak, is 'made:'by reference-to the perimeter l9!zand'notiby reference to theaxial lineofthe dop.

Thus, it will be seen that this :arrangement provides :means :to:predeterminedl-y measure off the distanced'on the'diiierentialbi-apothem, which :is also the major fdiametric chord intersector inreference to the 'chordal positionof the facet edge terminating inthetable I93.

It will alsoibe observed :thatrby this arrangement the wear and tear "onthe nose of the adapter l 60, due to the "difieren'ce inrhardness of the.diamond stock D and the materialof which theadaptor IBDis made, doesnot critically affect the installation.

Eccentricity due to :this type :of wear is compensated for by thecontrolas determined by the differential bi-apothem measurement.

The utilization of an anti-friction spring .zf'ed thrust bearing servesto press the stock D against the plate I68, with pressure permitting ofthe rotative indexing operation, withoutthe necessity for releasing thegrip upon the stock in movin from. one indexing position to another.This is ipeculiarly valuable in connection with the measurement gaugeprovided by this installation.

-While;I have described that the 'wcrkholder or dop and themeasurementgauge are;pecu1iare ly valuable informingthe 'crovvn facetswhere the diamonds run twenty or more to the karat, it is to beunderstood that the sameprinciple is involved-in the facetingrof largerstockmaterial, where thefaceting operation may be performed with unusualuniformity and more or'less automatically, so that assingleworkman'maysupervise a number'of machines simultaneously.

It will also'be understood that While Ihave .described andset'iorth'anarrangement for securing the most desirable results by employing thecomplete assembly, novelty is attributed to the use of segregated partsof the installation, as more specifically-set forth in the appendedclaims.

Having thus described-my invention and'illustrated its use, What I claimas new and desire to secure by Letters'Patent isz 1. In a dop providedwith. means =1or-rotationall-y mounting a gem withthergirdlei-portionexposed, the combination-comprising agirdle: guidemovable during rotation of thegem intaccordance with any eccentriclocation thereof, a contactarranged to-diametrically extenrlacross saidge1'n, said contact being mounted :to move inzsynchronism with saidguidewhereby tagauge the dis-,- tance for cuttin a facet on said gem.

:In a dopfor facetingthebezelof diamond stock having a pavilion:segment, a table and fa generally cylindrical segment 'p10Vidl1'lg ea:girdle, a mechanical dop having opposed seats for cengaging [said 1pavilion and table including :a body portion in which oneaof :said seatsis .ijourn'alled for indexing-anelectrical signalling system therefor,the combination of means to gauge the depth of .thefacet tolbeformedincluding aicontact arranged to lie on 'th'e' girdle ofthe diamondacarrier for said contact 'mounted on said body, including :means on thebody for: resiliently maintaining the contact in engagement with-"saidgirdle, a Ffa'cet sedge limiting control fcontact coupled to said.girdle contact :extended :toward Lthe opposite'side of said girdlewhereby the portion of said control :contactismade constantirrespectiveof eccentricityof 'said'diamond stock by the I indexing.means, whereby the difierential biapothem may be gauged during indexing,and electrical conductor means for connecting -=said contacts in saidsignal indicating system In a dop for faceting thebezel uponstock havinga pavilion segment and a table forming portion outlining therebetween a:girdle forming portion, said dop including opposed-seats forsaidpavilion and table, means for rotating saidpavilion engaging elementincludingindexing means, gauge means including a portion urged incontactwith said girdle and extendingdiametrically from said girdle'adjacent aportion of the stock to have a facet formed thereon, means on said tableengaging seat for guiding said gauging means slidably in relationthereto --whereby said gauging means is slid in any eccentric movementof said stock during indexing.

AVA dop for holding bruted gem stock for faceting the same'comprising abodyportionya pavilion seat and a table engaging seat axially disposedfrom said body, and'means for journailing said pavilion seat wherebysaid stock may be indexed while held between said seats, in combinationwith means'for gaugingtheditferential bi-apothem including means on saidbody supporting a girdle contact resiliently, a control contactdiametrically disposed with relation tosai'd stock and guided in saidtable-seat, means for adjustably positioning the girdle and controlcontacts in relation to 'ea'ch other whereby the predetermined depth offacet may be formedirrespective of any eccentric indexing of said stock.

5. In a diamondholderordon-a seat" against whieha diamond is held, aguide on the holder, a feed member adjustable along said guide, acontactfinger atone end of thefeed member and projecting" fromsaidguide, and adapted'to have its .end located inapredeterminedposition .relative to a diamond held against the seat,springmeans .engagingsaid feed'member and acting to urge the fingertoward the diamond, and at least one adjusting member on the .feedmember Ito determine the extent towhich theifinger. is urged by :thespring meanstoward the diamond, to indicate a point to which thediamondshall be ground.

.6. Ina-diamond holderorxdopas calledjorin claim 5, including'signallingmeans, :an' electric circuit "for actuating said signalling means, thediamond holder being so connected in said .circult together with the.ipolishin'g wheel against which it holds the diamond, that contact ofthe finger with isaid wheel will .close' the circuit, to actuate.the-signalling means.

'7. A'dop for faceting a gem havingragenerally cylindrical segment andca pavilion segment ineluding-opposed members, one for engaging thetable'forming portion of the gem, theioither .including a seat forengaging the pavilion forming portion, means for directing said memberstoward eachother .to'bind said gem andtto expose the girdle formingportion adjacent the bezel of said gem -and means for angularlydirecting said dop and holding it for "rotatably exposing said :girdleforming'portion in combination with agauging element carriedby one ofthe meme.

bers including a portion to contact the girdle forming portion andextending tea-point indieating the extent of the differential bi-apothemwhereby said point may serve to indicate the depth of cut of the facet.

8. In a diamond or the like polishing device including a den for holdinga bruted diamond stock defined by a generally cylindrical segmentterminating in a table and a pavilion, said dop comprising thecombination of a body portion, an axial member journ-alled therein, aseat on said member for engaging the pavilion of said diamond, anextension from said body including a plate for engaging the table ofsaid diamond, means for supporting said dop to direct the girdle formingportion to the polishing surface, an element carried by a portion of thebody contacting the girdle forming portion and having another portionextending diametrically across said gem to be polished to expose acontact portion spaced from the girdle contacting part and to contactthe stock to outline the differential biapothem, and to indicate on thestock the terminal edge of a facet, signalling means, an electricalcircuit for actuating said signalling means, said contact beingconnected in said circuit so that predetermined contact of the elementwit-h the polishing wheel against which the diamond is held will actuatethe signalling means.

9. In a diamond or like gem facet polishing device including thecombination with the dop for forming the facets by holding the gem toexpose the girdle portion adjacent a polishing surface of a lap and toform the facets adjacent the girdle comprising means to rotate-the gemto index it for the facets to be formed, including means to mount thedop and the polishing surface with respect to each other, of a gaugehaving a portion for contacting the girdle of the stock, and means formounting said gauge to yieldingly urge said portion into contact withthe girdle during indexing of the gem, and another portion of the gaugeto contact the stock to outline the differential bi-apothem to indicateon the stock the terminal edge of a facet and the distance to feed thestock and polishing surface with respect to each other.

10. In a diamond or like gem facet polishing device including thecombination with the dop for forming the facets by holding the gem toexpose the girdle portion adjacent a polishing surface of a lap and toform the facets adjacent the girdle comprising means to rotate the gemto index it for the facets to be formed. including means to mount thedop and the polishing surface with respect to each other. of a gaugehaving a portion for contacting the girdle of the stock, and means formounting said gauge to yield ngly urge said portion into contact withthe girdle during indexing of the gem, and another portion of the gaugeto contact the stock to outline the diff-erential bi-apothem to indicateon the stock the terminal edge of a facet and the distance to feed thestock and polishing surface with respect to each other, and signallingmeans to indicate when the gauged distance has been so fed.

11. In a dop for a bruted gem stock having a pavilion segment, a bezelforming segment and a girdle formed thereon, said dop including meansfor holding the gem stock upon a seat including indexing mean forrotatively applying said gem stock upon a polishing lap surface, thecombination of means to gauge the stock to indicate on the stock theterminal edge of a facet in the indexing positions of the stock, saidgauging means including a portion contacting the girdle of the stock andincluding another portion ex tending diametrically across the gem stockand toward the facet to be formed, to have an end of the latter namedportion indicate on the stock the terminal edge of the facet, asignalling device, an electrical circuit for actuating said signallingdevice, said portion extending diametrically across said stock beingconnected in said circuit of said device so that contact of the said endwith the polishing lap against which the gem is held will actuate thesignalling means.

12. In a d-op for a bruted stock having a table forming portion, agenerally cylindrica1 segment and a pavilion forming portion, stockholdin means comprising opposed seats on said dop, each having means forengaging the table and pavilion and including means for journalling saidholding means for rota'tably mounting the stock, means for indexing saidstock in accordance with the number of facets desired, the combinationof gauging means having oppositely spaced por 'tions, one portion ofwhich has a contacting area which ride on the said cylindrical segment,the other portion of which extends diarnetricalll across the stock tooutline on the stock the limits of the side of a facet coincident withthe differential bi-apothem which is positioned to contact grinding lapwhen a facet is completed, signalling means, and a connection betweensaid signalling means and gauging means for indicating said contact.

13. In a diamond holder or dop for facetlng gems including means forholding the gem against a polishing surface and axially adjustable onsaid dop for indexing, and with the girdle exposed to facet the gemcircumferentially adjacent the girdle and to one side thereof, thecombination comprising a gauge having a portion for contacting thegirdle of the gem stock and means for mounting said gauge, yieldingly tourge said portion into contact with the girdle of the gem during theindexing of the dop and another portion of the auge to contact the stockto outline on the stock the terminal edge .of a facet and the distanceto feed the stock and polishing surface with respect to each other, andsignalling means to indicate when the gauged distance has been so fed.

JOSEF HILLEL SPIRA.

REFERENCES CITED The following references are of record in the file ofthis patent:

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